This type of device is already known in principle from rail vehicle technology. In this regard, reference is made for example to the DE 20 2013 005 377 U1 printed publication.
Specifically, this prior art relates to a central buffer coupling for rail-mounted vehicles in which the coupling shaft of the central buffer coupling is articulated to the end face of a car body by a linkage so as to be pivotable in a horizontal direction. An elastomer spring mechanism is integrated into the linkage itself which serves in absorbing the tractive and impact forces occurring in normal driving conditions of the rail-mounted vehicle and being transmitted to a bearing block via the coupling shaft and the linkage.
The linkage known from DE 20 2013 005 377 U1 is moreover provided with a shock protector designed such that the connection between the linkage and the bearing block disengages upon the exceeding of a definable critical impact force transmitted via the coupling shaft and the linkage to the bearing block so that at least part of the coupling shaft can be taken out of the flow of forces transmitted to the bearing block. A shearing device comprising a plurality of shearing elements is used to this end by means of which the linkage, and specifically the housing of the elastomer spring mechanism of the linkage, is connected to correspondent vertically extending pivot pins.
The implementation of the shearing device with the linkage or respectively the housing of the elastomer spring mechanism being connected to the bearing block in the solution known from DE 20 2013 005 377 U1 can be regarded as being problematic. Specifically, the shearing device in the known prior art is realized by a plurality of shear pins (shearing elements), whereby the connection between the linkage and the bearing block is not disengaged until all the shearing elements have been activated and have lost their function as connecting elements. This assumes, however, that all the shearing elements are activated as simultaneously as possible upon the exceeding of a critical impact force transmitted from the linkage to the bearing block.
In practice, however, this condition cannot be realized or can only be realized at great effort since the load distributions on the shear pins employed as shearing elements is usually unknown and often uneven due to the elasticities and manufacturing tolerances in the system.
Moreover, the shearing elements (shear pins) employed in DE 20 2013 005 377 U1 not only serve solely as shock protection but also to connect the respective vertically extending pivot pins to the linkage, or the elastomer spring mechanism housing respectively, under normal conditions; i.e. when transmitting non-critical impact forces. The influence of the selected pretensioning of the pins on the response behavior and particularly the actuation force of the pins has to thereby be taken into account. Since the actuation force usually disperses, this additionally hampers realizing a simultaneous responding of the individual shearing elements upon a critical impact force being exceeded.
Moreover, only a lesser pin pretensioning is systematically possible in the case of pins concurrently serving as shearing elements compared to normal pins, which increases the risk of fatigue failure and the bolts working themselves loose.